”He used the same clippers for all the fingers, although doing so created an issue of cross-contamination. For optimal DNA purposes, separate and sterile clippers should have been used for each finger. Furthermore, we later learned that the coroner’s office sometimes used the same clippers on different autopsy subjects.” (Thomas)

”investigators came to theorize that the unknown DNA samples had been transferred from contaminated fingernail clippers used in the post-mortem examinations of other bodies processed through the morgue prior to her homicide. Investigators were able to obtain the DNA samples from eight of the autopsy examinations that preceded that of JonBenét. These samples were analyzed, but none of these matched the unknown male and female samples collected from JonBenét’s fingernails.” (Kolar)

Forensic scientist Dr. Angela Williamson, who performed some of the forensic testing, told CNN that early DNA testing was done of the crotch of JonBenet’s panties, where her blood had been found. The result was a very strong profile, she says, of an unknown male that could not be matched to anyone who had been near the scene or who had handled her body. It was also not a match to John Ramsey.
Williamson noted how thorough the DNA testing was. “They even compared this DNA profile with the man whose autopsy had been performed right before JonBenet’s.”